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ASCE 7-95 Wind Loads

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I believe that the requirements for wind loading at ridges is because ridges 
(or any other obstruction) causes high localized uplift forces.  Depressions 
(valleys) do not do the same thing.

I investigated the wind damage to a flat roofed, three story motel in which 
the rigid insulation and roofing had been torn off.  Large areas of damage 
occurred immediately downwind from small (1" diameter) electrical conduit 
that was installed across the roof.

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

Robert Rollo wrote:

. > I need additional opinions . . .
. > 
. > Wind loads per AISC 7-95.  Hipped roof (3:12) building in a "T"
. > configuration.  The standard now (versus 93) identifies the hip ridge
. > condition as a zone 2 "components and cladding" region for pressure.
. > 
. > How about the 2 valleys created by the "T" shape?  should these have a
. > zone 2 defined by the "a" width?
. > 
. > I have one 2 "yes" and 2 "no" votes on this one.  Additionally, the
. > widths are different as are the eave heights, so I have different widths
. > and "h" values.  Are there 2 seperate "a" zone widths, or does the
. > larger always apply (that would certainly be the conservative approach)?
. > 
. > Thoughts anyone?
. > 
. > Thanks in advance . . .